JPS6382407A - Auxiliary illumination control system for focus detector - Google Patents

Abstract

PURPOSE:To shorten time required for focusing of a focus detector and reduce power consumption for auxiliary illumination by auxiliarily illuminating all focus detection areas first and auxiliarily illuminating only a selected focus detection area at the time of following focus detection. CONSTITUTION:Three focus detection areas M, R, and L are provided for focus detection, and the illuminating light from an auxiliary illumination light source 4 is projected to an object, and the reflected light from the object is led to a focus detecting module 2 to detect the focus. The light source 4 has three light emitting parts, and all focus detection areas M, R, and L are illuminated with the light from all light emitting parts at the time of first focus detection in a focus detector. When the focus detection area where a principal object exists is selected by a selecting device, the distance measuring operation is performed for only this area and light emitting parts of the light source 4 are so controlled that the light is projected to only this selected focus detection area; and thus, the focusing operation speed is increased and power is economized.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an auxiliary lighting control system for a focus detection device, and is particularly suitable for controlling auxiliary lighting for focus detection in a camera having an exchangeable photographic lens. It is something.

(Prior Art) Conventionally, in Japanese Patent Application Laid-Open No. 60-256112, distance information about a plurality of objects is obtained by scanning a spot illumination beam for focus detection, and the closest object is focused. An autofocus camera has been proposed. In this conventional technique, the illumination light beam for focus detection is constantly scanned, and the illumination light beam is not fixed to the nearest object.

(Problems to be Solved by the Invention) In a focus detection device in which a plurality of focus detection areas are provided in areas other than the center of the photographing screen, it is necessary to extract the focus detection area that includes the closest subject, which is the main subject. It is desirable to perform focus adjustment for that focus detection area.However, distance measurement calculations are performed for all of the multiple focus detection areas, and the focus detection area that includes the closest subject is extracted based on the distance measurement calculation value. This method requires a large amount of time for calculations, etc., and has the disadvantage that it takes too much time to focus. Particularly when the subject is dark, the integration time of the CCD used as a focus detection sensor is also long, so the time required for focusing becomes even longer.

By the way, in cameras equipped with a passive focus detection device, when the subject is dark or has low contrast, the auxiliary illumination device installed inside the camera body emits auxiliary illumination light to illuminate the subject and perform focus detection. I'm trying to get it.

When such an auxiliary illumination device is used in a focus detection device having a plurality of focus detection areas as described above, it is desirable to emit a plurality of illumination light beams capable of illuminating each focus detection area. When using illumination light, the closest subject is often located in the focus detection area where the amount of light reflected from the subject is greatest, so by comparing the amount of light received in each focus detection area, you can determine whether the closest subject is present. It is considered that the time required for focusing can be reduced by extracting a possible focus detection area and performing distance measurement calculations and focus adjustment only for that focus detection area. In addition, during subsequent focus detection, it is useless to illuminate the focus detection area where the amount of reflected light is small, so the configuration should be configured so that only the focus detection area where the nearest subject is likely to be present and where the amount of reflected light is the highest is illuminated. For example, it is thought that the power consumption of the auxiliary lighting device can be saved.

The present invention was made based on this knowledge, and its purpose is to provide auxiliary illumination to all focus emitting areas at the time of initial focus detection, and to illuminate the focus detection area where the amount of reflected light from the subject is greatest. To provide an auxiliary illumination control system for a focus detection device, in which a power source for auxiliary illumination can be saved by selectively illuminating only the selected focus detection area during subsequent focus detection.

(Means for Solving the Problems) As shown in the accompanying drawings, the auxiliary lighting control system for a focus detection device according to the present invention includes a focus detection device having a plurality of focus detection areas within a photographing screen; an auxiliary illumination device comprising a plurality of light emitting sections each emitting illumination light flux capable of illuminating each focus detection area, and emitting light from all the light emitting sections so as to illuminate all the focus detection areas when the focus detection device first detects focus; , selection means for selecting a focus detection area, and the auxiliary illumination device is configured to emit light only from a light emitting unit that illuminates the selected focus detection area when a focus detection area is selected by the selection means. It is made up of

The selection means may be configured to compare the magnitude of the amount of reflected light from the object of the illumination light flux for each focus detection area at the time of the first focus detection, and select the focus detection area with the largest amount of reflected light from the object. It is suitable if

According to the present invention, the focus detection device has a plurality of focus detection areas, and the auxiliary illumination device has a plurality of light emitting units that each emit an illumination light flux capable of illuminating each focus detection area. . At the time of initial focus detection, all the light emitting parts are controlled to emit light, and all focus detection areas are illuminated. The illumination light flux from each light emitting unit is projected onto a subject within the photographic screen, and reflected light of the illumination light flux is obtained from the subject. The amount of reflected light from the subject of the illumination light flux is compared for each focus detection area.The focus detection area with the largest amount of reflected light is likely to include the closest subject that will be the main subject, so usually , the focus detection area with the largest amount of reflected light from the subject is selected by the selection means. When a focus detection area is selected by the selection means, the auxiliary lighting device controls only the light emitting section that illuminates the selected focus detection area.

(Example) Figure 1 shows the photographic lens attached to the front of the camera body, and is used to explain the principle of the active AF system. The subject light incident from 1) is received by the focus detection module (2) installed inside the camera body,
Performing focus detection based on received light data (5a) to (5)
The range indicated by b) is the focus detection area. This camera body is equipped with an auxiliary illumination optical system (3, 4) for focus detection, and when the amount of light on the subject is insufficient, such as at night, the auxiliary illumination optical system projects auxiliary illumination light onto the subject. , and is configured so that focus detection can be performed using the reflected light. (4) is a light source, and (3) is a light projection lens for condensing the light emitted from the light source (4). The range shown by (6m) to (6b) indicates the area of the projected light beam.

Fig. 2 is a perspective view of a camera as an embodiment of the present invention incorporating an active AF system based on the above principle. In Fig. 0, (10) is the camera body, and (11) is the photographic lens (1). It is an interchangeable lens equipped with. The camera body (10) has a window (
12) is provided.

(13) is a shutter button, and as will be described later, a focus detection operation is started by touching this shirt button (13).

FIG. 3 is a diagram showing an example of a focus detection optical system having a plurality of focus detection areas. In FIG. It shows the area through which the focus detection light flux passes on the pupil plane. (101) is a focus detection area mask placed immediately after the planned focal plane (not shown), and has three apertures (101a), (10l b), (10l b) as shown in the figure.
1c), which determine three focus detection areas on the photographic screen. The aperture (101b) is provided approximately in the center of the photographic screen, and the aperture (Iota) and (101cH) are provided in areas other than the center of the photographic screen.These three apertures (101m), (10l b)
), (101c) are rectangular in shape, and the opening (
101b) is arranged in the center of the shooting screen with its longitudinal direction facing left and right, and the openings (101a) and (101a)
are arranged parallel to the lateral direction of the aperture (101b) and symmetrically with respect to a straight line passing through the optical axis of the photographic lens (1), with the longitudinal direction being in the vertical direction. Note that this arrangement shows one example, and is not limited to this. (102a), (102b), (1
02c) are the above openings (Iota).

(10lb) and (101c), and is a condenser lens placed immediately after the aperture mask openings (103a) to (101c).
103f) on the exit pupil plane of the photographic lens (1). That is, the aperture mask aperture (103a
) and (103b) are formed by the condenser lens (102b) on the exit pupil plane of the photographing lens (1), respectively.
00a) and (100b), and the aperture mask aperture (
103c) and (103d) are condenser lenses (102
a), the images are formed into areas (100d) and (100c), respectively, on the exit pupil plane of the photographic lens (1), and the aperture mask apertures (103e) and (103f) are formed by the condenser lens (
102e), the images are formed into areas (100d) and (100c) on the exit pupil plane of the photographic lens (1), respectively. In this way, the aperture mask openings (103a) to (103f) serve to determine the focus detection light flux area on the exit pupil plane of the photographic lens (1).

Immediately after the aperture mask (103), an imaging optical member (10
4) is located. Imaging lenses (104a) to (104f) are formed in the imaging optical member (104), and aperture mask apertures (103a) to (103f) are formed, respectively.
is placed in the optical path of the These imaging lenses (10
4a) to (104f) are for re-imaging the image formed near the focal plane on the AF light receiving element surface (105). (106a), (106b), and (106c) are focus detection sensors composed of one-dimensional sensors (line sensors) such as COD;
) is configured to receive the images formed by the imaging lenses (103a) and (103b), and the sensor (106b) is configured to receive the images formed by the imaging lenses (103e) and (103f). , the sensor (106e) is arranged to receive images formed by the imaging lenses (103c) and (103d).

That is, these sensors (106m), (106b
), (106e) are the aperture mask aperture (103a) and (1
03b), (103e) and (103f), (103c)
For example, the sensor (106a) can detect an image formed through the aperture mask aperture (103a) and an image formed through the aperture mask aperture (103). The focal state of the photographic lens (1) is detected by taking the correlation with the . Aperture mask aperture (10
The alignment direction of (3m) and (103b) is the opening (101b)
It is arranged along the longitudinal direction. The direction in which the aperture mask apertures (103c) and (103d) are arranged is such that the aperture <10
1 m) along the longitudinal direction. The direction in which the aperture mask apertures (103e) and (103f) are arranged is the aperture (
101c) along the longitudinal direction. Therefore, the line direction of the sensor (106a) and the sensor (10
6b) and (106c) are different by 90°. Since the sensors (106a) are arranged in the left and right direction, they have a focus detection ability for subjects with contrast in the horizontal direction, and the sensors (106b) and (106a)
Since the lenses 6e) are arranged in the vertical direction, they have a focus detection ability for subjects having contrast in the vertical direction.

Figure 4 shows an example of the viewfinder field image.
200) shows the entire shooting screen, (200a),
The areas indicated by (200b) and (200c) indicate the focus detection area, and the sensor (106g).

This corresponds to the light receiving areas (106b) and (106c). When the focal length of the photographic lens (1) changes, the focus detection areas (200a), (200b), (2
00c) changes as shown in FIG.

In Fig. 5, when the focal length of the photographing lens (1) is f, the focus detection area (200 m) in Fig. 4 is (M>
(200b) corresponds to (R), and (200c) corresponds to (L). Here, the focal length of the photographic lens (1) is f
/2, the focus detection area (M) is (M2)
, (R) changes to (R2), and (L) changes to (R2). When the focal length of the photographic lens (1) becomes 2×f, (M> becomes (M3), (R) becomes (R3), and (
L) changes to (R3). As the illumination area for illuminating such a focus detection area, the focal length of the photographic lens (1) is limited (for example, limited to the range of f/2 to 2×f). In this case, all you need to do is to illuminate as shown in (m), (r), and (f).By doing this, all of the It becomes possible to illuminate the focus detection area. In addition, for a photographic lens (1) having a focal length outside the predetermined range, by illuminating only the illumination area (m),
Power consumption can be reduced by lighting only the focus detection area in the center.

Next, Figure 6 shows the illumination areas (m), (r), (1
An example of an auxiliary lighting device for illuminating 3 is shown. Figure 6 is a cross-sectional view of the auxiliary lighting device, (3) is a floodlight lens,
(7) is a pattern surface for adding contrast to the illumination luminous flux, and (4) is three light emitting parts (LDI) and (LD2).

This is an LED for the auxiliary illumination light source waiting for (L D 3),
The front part has three spherical lens parts. In addition, the light emitting part (
A reflective surface is formed around each of the light emitting parts (LD,
), (LD a), and (LD 3) as well as side lights are efficiently used as illumination light. Regarding operation, the light is focused by the surface lens section, and the side light is directed forward by the reflective surface, then focused by the spherical lens section, illuminates the pattern surface (7), and then passes through the projection lens (3).
) is projected towards the subject. This luminous flux corresponds to the illumination area (arrow) in FIG. Similarly, the light emitting part (LD2)
The luminous flux from the light emitting part (L
The luminous flux from D corresponds to the illumination area (1) in FIG. By adopting such a configuration, the illumination areas (+i) and (r) as shown in FIG.

(1) can be obtained, and all focus detection areas can be auxiliary illuminated for a given focal length of the photographic lens (1).

Next, a control system of a camera including the above-mentioned focus detection device and auxiliary illumination device will be explained using FIG. 7.

FIG. 7 is a block diagram showing an example of a focus detection system. (300a) to (300e) are CODs used for the aforementioned focus detection sensors (106a) to (106c), and (301) is an analog signal-digital signal (
A/D) CCD drive circuit including conversion circuit, fL Chico bond old reichu m^/'/' n /riheheha~ltsu00c
) converts the analog signal output from
(300c)
) to (300c). (302) is a digital memory circuit that stores digital signals output from the CCD drive circuit (301). (303)
is a control arithmetic circuit that controls the system and also outputs from the focus detection C0D (300a) to (300c), converts it into a digital signal in the CCD drive circuit (301), and stores it in the digital memory circuit (302). The data is processed according to a predetermined algorithm, and the photographic lens (1
) and a defocus direction signal are output. (304) is a subtraction circuit, and a control calculation circuit (304) is a subtraction circuit.
The output signals of 3) (defocus amount and defocus direction signal) and correction data (C) regarding the spherical aberration of the photographic lens (1) output from the register circuit (313) are input, and the defocus amount is corrected. Data (C) is subtracted and output together with the defocus direction signal. (305
) is an addition circuit, into which the output signal of the control calculation circuit (303) and the correction data (C) regarding the spherical aberration of the photographing lens (1) output from the register circuit (313) are input, and Correction data (C) is added and output together with the defocus direction signal. (306)
is a selector circuit, which receives the output of the subtraction circuit (304) and the output of the addition circuit (305) as input, and is further given either a positive or negative signal from the register circuit <313>. Then, the subtraction circuit (30
4) is selected, and if the signal is a positive signal, the output data and direction signal of the adder circuit (305) are selected and output. Selector circuit (30
The data of the defocus amount selected in step 6) is sent to the multiplication circuit (310).

The display comparison circuit (307) and the 0 multiplication circuit (3
10) is provided with a conversion coefficient (K) for focus adjustment from a register circuit (314).

This conversion coefficient (K) includes information on the mechanical configuration of the 8-lens dynamic system (for example, information on helicoid leads, etc.) necessary to obtain lens movement corresponding to the amount of defocus, and The required number of rotations (N) of the motor (MT) can be obtained by multiplying by the conversion coefficient (K). Data on the motor rotation speed (N) and a signal indicating the rotation direction are given to a motor drive circuit (311). (
Reference numeral 307) is a display comparison circuit to which the above-mentioned defocus amount and in-focus data from the in-focus data circuit (308) are input, and these two data are compared to determine in-focus or out-of-focus. Outputs the determination result of focus. (309) is a display device which inputs the output of the display comparison circuit (307) and the defocus direction signal output from the selector circuit (306), and indicates whether the focus is in focus, out of focus, or out of focus. If so, the direction is also displayed.

As described above, data on the motor rotation speed (N) and a signal on the rotation direction are input to the motor drive circuit (311), and the motor (MT) is rotated according to these information. The rotation of the motor (MT) is caused by slippage and gear train (GT) as shown by the dotted line! 1 (SL) to the drive shaft (DA). An encoder made of a photocoupler (PC) is provided at a position after passing through the slip mechanism (SL), which monitors the rotation of the drive shaft (DA) and feeds it back to the motor drive circuit (311), thereby controlling the motor (MT). ) by a predetermined amount.

(312), (313), and (314) are register circuits, and the reading circuit (RD) allows the photographing lens (1) to
focal length information (f), correction data (C) regarding aberrations of the photographic lens (1), and conversion coefficient (K) for focus adjustment are read and stored. (31
5) is a decoder circuit, which decodes the signal output from the register circuit (312) and generates the illumination area signal "a".
”, depending on the focal length of the photographic lens (1).
Outputs a signal of "h" level or "Low" level.

That is, if the focal length is such that it can illuminate the off-axis focus detection area, a "High" level signal is output, and if the focal length is other than that, a II Lo, II level signal is output.

(250> is an inverter, and the lighting area signal “a”
is inverted. (251) is an AND circuit, which uses a logic bond between the auxiliary light emission signal “2.” and the inverted signal of the illumination area signal “a” to be described later, to generate a screen white display driver (25
2) Turn on and off the on-screen display driver (252
> is a display device (such as a liquid crystal) in the viewfinder (255).
A transparent electrode (253) is connected between the screen white display driver (252) and the display device (253).
54). On the other hand, the lighting area signal “a”
” is also input to the control calculation circuit (303).

Auxiliary light emission signal "g1'" from the control calculation circuit (303)
, "FIz" + "lF3" are the LED light emitting parts (
t, D,).

(LD, 3) is controlled so that, for example, when the signal "gl" becomes "High" level, the transistor (260) is ONL and the light emitting part (LD,) lights up. .Similarly, the signals “g2” and “fls
” reaches the “)ligl+” level, the transistor (
261) and (262) are turned on, and the light emitting parts (L
D, (LDs') lights up. (324) is a trigger circuit, and the shutter button is a separate switch that turns on and off.
A focus detection start signal is generated in accordance with the FF, and the signal is given to the control calculation circuit <303>. (
325) is a photometry circuit that measures the subject brightness in each focus detection area, and when the subject brightness is lower than a certain level, a control calculation circuit (303) sends a signal "d" to turn on a light emitting diode. Output to.

The configuration of the camera body (10) side has been described above, and next, the configuration of the interchangeable lens (11) side will be explained.

The interchangeable lens (11) is shown separated by two dotted silver lines at the lower left in FIG. 7, and is detachable from the camera body (10). This is the lens. (ZR) is a zoom ring that can be operated from the outside, and the zoom ring (ZR)
A brush (BR) is attached that can rotate integrally with the brush. A code plate (CD) is provided on the lens barrel fixing part (not shown) corresponding to the brush (BR) of the zoom ring (ZR), and the code plate (CD) is provided in the lens barrel fixing part (not shown) to correspond to the brush (BR) of the zoom ring (ZR). It is configured to be able to generate a digital code signal according to the focal length. The code signal is provided in the interchangeable lens (11) and is connected to be input to a lens information output circuit (L r D) including a ROM. R included in the lens information output circuit (LID)
The address of the OM is specified by a digital code signal, and the focal length information (f) of the above-mentioned interchangeable lens (11) is determined according to the start of reading from the reading circuit (RD) on the camera body (10) side.

Correction data (C) regarding aberrations and motor rotation speed conversion coefficient (K) are read, and each is sent to a register circuit (312).
), (313), and (314). The values of the focal length information (f), aberration correction data (C), and motor rotation speed conversion coefficient (K) of the interchangeable lens (11) are updated according to the zooming of the interchangeable lens (11), and the reading circuit (RD) is output. As a terminal between the camera body (10) and the interchangeable lens (11),
A power terminal, a synchronous clock pulse terminal, a read signal terminal, a serial data terminal, and a ground terminal are provided. Further, in order to drive the focusing lens, the driven shaft (FD) is in meshing engagement with the focusing ring (FR).

The operation will be explained below.

When the interchangeable lens (11) is attached to the camera body (10), the lens information output circuit (LID) and reading circuit (R
D) is connected via a terminal, and the ground terminal is similarly connected. Furthermore, in order to move the focusing ring (FR), mechanical engagement between the drive shaft (DA) and the driven shaft (FD) is achieved by the projections and depressions provided on both shafts.

When the user touches the shutter button (13) etc. to perform focusing, power is first applied from the readout circuit (RD) to the lens information output circuit (LID) via the power supply terminal, and then to the synchronization clock pulse terminal and the readout circuit. R from the lens information output circuit (LID) according to the read signal of the signal terminal.
The contents of the OM are read, focal length information (f) is sent to the register circuit (312), correction data regarding aberration (C) is sent to the register circuit (313), and the rotation speed conversion coefficient (K) of the motor (MT) is sent to the register. It is taken into the circuit (314). This import will continue at predetermined timings,
Data is updated from time to time. The contents of this ROM to be read are determined by the position of the brush (BR) that moves according to the setting of the zoom ring (ZR).
)'s digital co.

- Determined by the address specified by the code signal.

Therefore, even if the focal length changes due to zooming, for example, the focal length information (f) is included in the contents of the ROM accordingly, so it is not transmitted through the lens information output circuit (LID) and reading circuit (RD). and is taken into the register circuit (312). When the above data acquisition is completed, the control calculation circuit (303) sends the CC via the signal line "e=1".
D [motion pulse is given to the CCDII motion circuit (301). When the above COD drive pulse is given to the CCD drive circuit (301), the CCD drive circuit (301)
The drive start signal is COD (300a) to (300a) for focus detection.
300C) and each CCD (300a) to (30
The analog signal generated at the CCD drive circuit (30
1) is converted into a digital signal by the A/D conversion circuit provided in step 1). In addition, if the analog signal is delicate, C
The signal is multiplied by a constant in the analog gain control in the CD (dynamic circuit <301), then A/D converted and converted into a digital signal. The digital signal is transferred to a digital memory circuit (302) and stored in memory. In addition, within the digital memory (302>), CCD (300a), (300
b), (300c>) storage addresses for each data are set in advance.

On the other hand, the photometry circuit (325) outputs information on the brightness of the subject in each focus detection area to the control calculation circuit (303) via the signal line "d". Here, the measurement circuit (32
5) has a configuration as shown in FIG.

In FIG. 9, the light receiving elements (20a), (20b), (
20c) are the focus detection areas (200
The brightness of the subject in areas (200a'), (200b'), and (200c'), which are approximately the same as a), (200, b), and (200e), is monitored, and the respective outputs are sent to the A/D conversion circuit ( A/D at (21m), (2l b), (21c)
After conversion, the respective discrimination circuits (22m) and (22b)
, (22c) are input to the 6-discrimination circuit (22m), (2
In steps 2b) and (22c), the data in the comparison data memory (23) set in advance is compared with the data after A/D conversion to determine whether the brightness is at a predetermined brightness level, and the results are compared. Output to the circuit (24). Comparison circuit (24)
Then, the luminance differences of the light receiving elements (20m), <20b), and (20c) are compared to determine whether they are equal or not, and the result is output to the logic circuit (25). The logic circuit (25) transfers the 4-bit signals shown in Table 1 corresponding to the discrimination circuits (22a), (22b), (22c) and the comparison circuit (24) to the control calculation circuit (303). In the control calculation circuit (303),
This 4-bit signal determines whether the light emitting diode is lit or not.

(Margin below) Table 1 Also, an example of the arrangement of the photometric circuit (325) is shown in factor 10. In the figure, (31) is a half mirror 1, (32) is a submirror, (33) is a focus plate, (34) is a pentaprism, (35) is an eyepiece, and (36) is a beam splitter. Focus plate placed on film screen (33)
Part of the light from the pentaprism (3
4) and the photometric circuit (3) at the beam splitter (36).
25). Note that the optical configuration of the photometric circuit (325) is not directly related to the present invention, so the explanation will be omitted and the explanation will return to FIG. 7.

Based on the photometric value output from the photometric circuit (325), the control calculation circuit (303) detects a focus detection CCD (300m) when the value is darker than a predetermined level.
At the same time as the integration of the signal output from (300c) starts, any or all of the auxiliary light emission signals "wa" to "ha" are set to High level, and the light emitting diode is turned on. If the photometric value is brighter than a predetermined level, the auxiliary light emission signal “t,
” to “c” are set to “Low” level, and the light emitting diodes are turned off.

As mentioned above, the focal length information (f) of the photographic lens (1) is stored in the register circuit (312), and as a result of decoding this focal length information (f) by the decoder circuit (315), the decoder circuit When the illumination area signal “a” output from (315) is at “High” level, the control calculation circuit (303) outputs the auxiliary light emission signal.
", "g2", "g," are all set to the "'High" level, and when the illumination area signal "a" is at the 'Low' level, only the signal "2." is set to the "High" level. This is because the focus detection area (LD,) is arranged so that the LED light emitting unit (LD), which is lit when the signal g1°° is at the "High" level, measures the center of the photographic screen.
For example, the area (M) within the illumination area (,, +) in Figure 5
etc.).

The light emitted from the light emitting diode is projected onto the subject,
The light reflected by the object passes through the photographic lens (1) and enters C0D (300a) to (300C) for focus detection. When the reflected light incident on the focus detection CCDs (300a) to (300c) reaches a certain level, the focus detection CCDs (300a) to (300e) send a "High" signal to the control calculation circuit (303). Level integration completion signals "h," to "h," are output. CCD for focus detection
(300a) to (300c) control calculation circuit (30
3) Integration completion signal ``'Higl+'' level ``l++''
” to “h3°” is output, the control calculation circuit (303
) stops the integration operation of the CCD via the signal line "e" and at the same time sets the auxiliary light emission signals "2.' to 11, .11" to the "LO-" level to stop the light emission of the light emitting diode.

As mentioned above, when the CCD integration operation is completed, the CCD
The analog signal output from the COD drive circuit <30
The signal is converted into a digital signal by the A/D conversion circuit provided in 1), and is transferred to the digital memory circuit (302) and stored in memory. When the memory to the digital memory circuit (302) is completed, the control calculation circuit (303) stores the input data in each C according to a predetermined algorithm.
Calculation processing is performed for each CD data, and the defocus amount and defocus direction signal at that time are determined from the phase difference between the correlation signals of the CCD lines. Then, one of the defocus amount and defocus direction signal obtained from each CCD data is made valid according to a predetermined algorithm. This defocus amount ΔL and the defocus direction signal are processed by a subtraction circuit (3
04) and an adder circuit (305). On the other hand, a correction value (C) is output from the register circuit (313) and input to one input terminal of the subtraction circuit (304) and the addition circuit (305). In addition to the above-mentioned correction value (C), a correction direction signal (+) or (-) is supplied from the register circuit (313) to the selector circuit (306).

Then, according to the correction direction signal output from the register circuit (313), for example, if it is a (-) signal, the subtraction circuit (30
The data and direction signals from 4) are sent to the selector circuit (306
), and if it is a (+> signal, the adder circuit (305)
Data and direction signals from the selector circuit (306) are taken into the selector circuit (306). The data and direction signal selected by the selector circuit (306) are given to a multiplication circuit <310) and a display comparison circuit (307), and the multiplication circuit (310) outputs the defocus amount data to the motor from the register (314). (MT) is multiplied by the rotation speed conversion coefficient (K) and the rotation speed data (N) obtained in the multiplication circuit (310) is given to the motor drive circuit (311).
07), the defocus amount data and the in-focus data circuit (
A comparison is made with the data of 308), and if the defocus amount data is within a predetermined in-focus range, the focus display element (the round display section at the center of the display device (309)) is turned on. The selector circuit (306) further sends a signal in the defocus direction to the motor drive circuit (311) and the display device (30).
9), which instructs the rotation direction of the motor (MT) and also controls either the left or right of the out-of-focus display element (triangular display part of display device Z (309)) to display the defocus state. Turn it on. The motor (MT) receives motor rotation speed data (
N) and rotates according to the rotation direction signal. Motor (MT)
The rotation of
) through the driven shaft (FD) of the focusing ring (F
R) to move the focusing optical system (not shown) in the optical axis direction by the amount of defocus. The rotation of the drive shaft (DA) is monitored by an encoder made of a photocoupler (PC), and is accurately controlled by feeding back to the motor drive circuit (311).

Here, the case where the illumination area signal "a" is at the "Low" level will be described in more detail. Decoder (315
) The illumination area signal “aIT” output from
level means that the focal length of the interchangeable lens (11) is outside the predetermined range.In this case, even if the LED light emitting part (LD) and (LD3) are lit , the off-axis focus detection area cannot be illuminated, therefore in this case the light emitting part of the LED (L D 2)
, (L D 3) is meaningless,
Since this is a waste of power, the control calculation circuit (303)
The auxiliary light emission signals "gl" and "fico" are set to the "Low" level, and the lighting of the light emitting parts (LDl) and (LD3) is prohibited. Then, the auxiliary light emission signal “gl”
Only the light emitting part (L D l) is set to "High" level.
The only light emitting part is the light emitting part.゛Also, when the illumination area signal “a” is at the “Low” level and the auxiliary light emission signal “gl” is at the “High” level, the output of the AND circuit f¥8 (251) is “High”.
level, the screen white display driver (252) is turned on, the display device (253) in the finder is turned on, and the photographer is informed that only the center focus detection area is valid. And also control (wholesale calculation circuit (3)
03) selectively extracts only the data of the central focus detection area, in this case, the data of C0D (300a), from among the data in the digital memory (302),
Distance calculation is performed only for that area. By doing so, it is possible to increase the distance measurement calculation speed to MWJ.

Next, a case will be described in which, when the illumination area signal "a" is at the "High" level, the photometry circuit (325) determines that the brightness of the subject in each focus detection area is equally dark. When the illumination area signal "a" output from the decoder circuit (<315) is at the "High" level, it means that the focal pressure of the interchangeable lens (11) is within a predetermined range. , light emitting part (L D l
), (L D 2), and (L D 3), the off-axis focus detection area can be illuminated. In this case, the control calculation circuit (303) changes the auxiliary light emission signals “g1”, “1F2”, “g,” to “High11”.
As the level, the light emitting part (L D I), (L D
2), (L D 3) is lit. In addition, the control calculation circuit (303) measures the difference in the timing of generation of the integration completion signals "11.", 11□", and "+13" that are output when the COD receives a predetermined amount of light, and integrates the signal as early as possible. Data in the digital memory (302) is selectively extracted for the COD that has issued a completion signal, and distance measurement calculations are performed only for that area. Since the amount of reflected illumination light from the Since this is the main subject that you most want to photograph, this is a very suitable focus detection area selection.

When the focus detection device is activated continuously, as in the case where the shutter switch (13) etc. is maintained in the ON state, the LED light emission for the second and subsequent times is changed to the CCD that was activated last time. By limiting the focus detection area to only the LED that illuminates it, it is possible to save power.

In other words, when the last valid CCD is C0D (300a), the control calculation circuit (303) sets only the signal "3" to the HiHI+" level to cause only the light emitting part (LD+) to emit light, and similarly, the ccD (300b), only the light emitting part (LD2) is made to emit light, and when the CCD (300c) is dry, only the light emitting part (LD3) is made to emit light.

Also, even if a predetermined time elapses, the integration completion signal ゛h,'',
When "h2" and "h," are not generated, the control calculation circuit (303) sends an integration end signal to the CCD drive device (301) via the signal line "e". In this case, the CCD drive device (301) forcibly stops the integration of each COD and starts data acquisition. CCD drive device (301)
Built-in is an analog gain control circuit that amplifies the analog data by a predetermined amount according to the amount of light received by each CCD (300a) to (300c).
x 1 , x2. x4. Each CCD data is multiplied by any one of x3 as a gain amount. This gain amount is stored in the control calculation circuit (30) through the digital memory (302).
3). The control calculation circuit (303)
Compare the gain amount of D and select C0D(
The CCD with the largest amount of illumination light reflected from the subject is enabled, and distance measurement calculations are performed only for that COD.Furthermore, from the second time onwards, the LED light emission is based on that CC, as described above.
By lighting only the LED light emitting unit that illuminates the focus detection area for D, it is possible to save power.

If the gain amount is equal and minimum for the two CCDs, the distance measurement calculation is also performed for the two CCDs, and the next LED light emission is performed by the two LED light emitting units that illuminate the focus detection areas of the two CCDs. It is possible to limit the Furthermore, if the three CCDs have the same gain amount, it is necessary to perform distance measurement calculations on all CCD data and to emit light from all the LED light emitting parts for the next LED light emission.

As described above, the magnitude of the illumination light from the subject is determined based on the difference in the generation point of the integration completion signal of each CCD and the gain amount of the analog gain control, and focus detection is performed when the nearest subject (main subject) is present. Select an area and
By performing distance measurement calculation only for that area, the distance measurement calculation speed becomes faster. Furthermore, from the second time onwards, the power source can be saved by limiting the light emission of the LED to illuminating only the focus detection area selected last time.

In the above explanation, the photometry circuit (325) has determined that the brightness of the subject in each focus detection area is equally dark, but on the contrary, it has been determined that each focus detection area has different brightness. Let me add some information about the case.

In this case, the constant light is different for each focus detection area, and it is difficult to determine the amount of light received by each COD.
Since it is no longer possible to determine that the closest subject exists in the focus detection area, it is necessary to perform distance measurement calculations for all areas and to light all the LED light emitting parts for the next LED light emission.

The above operation is shown in FIGS. 8(a) to 8(d). Figure 8 (a
) to (d) are flowcharts showing operations for selecting an effective ranging area and selecting an auxiliary light emitting area by the control calculation circuit (303). However, here, if there are two or more minimum values of the gain amount, all areas are made valid and all the auxiliary lights are also emitted.

The following description will be made according to the step numbers attached to the flowchart.

In step #1, a variable 5T=O is set to indicate that this is the first distance measurement. In step #2, it is checked whether the illumination area signal "1a1" is at the "High" level.The state where the illumination area signal "I," is at the "HigI+" level means that the illumination area signal "1a1" is at the "High" level. An interchangeable lens (11) with auxiliary illumination (also capable of illuminating the distance area) is attached. In step #3, the photometric circuit (3
Based on the output of step 25), it is determined whether the three ranging areas have the same brightness. In step #4, the photometric circuit (32
In order to show that the output of 5) is different for the three ranging areas, let S=O. In step #5, all of the auxiliary light emission signals "21", "81g2"+", and IF3" are set to "High" level (lit).In step #6, the output of the photometry circuit (325) is set to the three distance measurement areas. In order to show that the brightness is equivalent to that of , S = 1.In step #7, it is determined whether this is the first ranging operation or not using the variable ST.In step #8, the illumination area signal It all is at the "Low" level, the auxiliary light emission signal ° "gl" is set to the "High" level (lit), and "2□", "g," are set to the 'Low' level (
In step #9, the auxiliary light emission signal “
2. ", "g2"%'#s" are output to each LED light emitting section. In step #10, the counter T that controls the longest integration time of the CCD is reset and started. In step #11, a CCD drive start signal is sent via the signal line "e". In step #12, it is determined whether the longest COD integration time has elapsed. In step #121,
Sends COD [motion end signal] via signal line IteI+. In step #13, the illumination area signal ° “a” is set to “H”.
Step #14
Now, it is determined whether S=1. In step #15, the gains iGA, GB, and GC of each CCD line are read from the digital memory (302). In step #16, it is determined whether GA is smaller than the smaller value of GB and GC. In step #17, the auxiliary light emission signal "gl" is set to the "Higl+" level (lit), and the "g2pa" and "ri" are set to the "Low" level (not lit). In step #18, GB is set to GA, It is determined whether the value is smaller than the smaller value of GC.In step #19, the auxiliary light emission signal ``9□'' is set to ``High'' level (lit).
g I ” + “g,” to “Low” level (not lit)
In step #20, it is determined whether GC is smaller than the smaller value of GA and GB. Step #2
1, the auxiliary light emission signal "g," is set to 'High' level (lit), and "3." ”, “2□” are set to “Lo-” level (non-lighting). In step #22, the auxiliary light emission signal “
It is determined whether "fir" is at the "High" level.

In step #23, it is determined whether the integration completion signal "hI" of the CCD (300a) is at the "High" level (integration completion).In step #24, the auxiliary light emission signal "hI" is determined.
It is determined whether 2'° is at the "High" level. In step #25, it is determined whether the integration completion signal "1.2++" of the CCD (300b) is at the "High" level (integration complete). In step #26, the auxiliary light emission signal “
It is determined whether g and pa are at the 'High' level.In step #27, the integration completion signal of C0D (300c) is determined.
113" is at the "Higb° level (integration complete). In step #28, it is determined whether the illumination area signal ゛a゛ is at the 'High' level.In step #29, it is determined whether S=1.In step #30, the auxiliary light emission signal ``FI+'' is determined. “High”
Level (lit), "f12", 2. In step #31, it is determined whether S=1. In step #32, the auxiliary light emission signal "fix" is set to 'Higb' level (lighting). “2,
-“2.’° is set to “L, ow” level (non-lit),
In step #33, it is determined whether S=1.

In step #34, the auxiliary light emission signal '3. ”H1g
h” level (lit), and “IF+” +゛″2□” are set to “Low” level (not lit). Step #35
Now, the CCD integration completion signal "t+, -'"11□
”, “h, ′ are all at the “High°” level. In step #36, the auxiliary light emission signal "i
It is determined whether 9+" is at the High" level. In step #37, CC is stored in the digital memory (302).
Read the data of D (300a).

In step #38, a distance measurement calculation is performed from the data of the CCD (300a), and in step #39,
The distance measurement calculation value for a) is invalidated.

In step #40, the auxiliary light emission signal '''3□'' is
Determine whether the level is “Highb”. Step #41
Now, from the digital memory (302) to the CCD (3001)
”) In step #42, ccD
Distance calculation is performed using the data (300b).

In step #43, the distance measurement calculation f-direction for ccD (300b) is invalidated. In step #44, it is determined whether the auxiliary light emission signal "11 y" is at the "Higb" level. In step #45, the digital memory (
302) reads data from the CCD (300c). In step #46, a distance measurement calculation is performed based on the data of the CCD (300c). In step #47, the CCD (30
The distance measurement calculation value for 0c) is invalidated. Step #
48, CCD (300a), (300b), (30
From the distance measurement calculation values for 0c), select the calculation value to be valid. In step #49, 5T=1 is set to indicate that this is the second or subsequent distance measurement.

Here, for example, the illumination area signal “a++” is “High”.
The operation when the output of the photometering circuit <325) is the same for the three distance measurement areas will be explained with reference to FIG. 5T=0 is set as a variable to indicate.Next, in step #2, it is determined whether the illumination area signal "an" indicating whether an interchangeable lens (11) with a predetermined focal length is attached is at the 'High' level. Here, the illumination area signal “a” is “High”.
When the illumination area signal "a" is at the "Higb°" level, the process proceeds to step #3. When the illumination area signal "a" is at the "Higb°" level, the three ranging areas can be auxiliary illuminated. In step #3, the photometry circuit (325) It is determined whether the outputs of the photometry circuit (325) are equivalent for the three distance measurement areas.Here, it is assumed that they are equivalent, and the process proceeds to step #6.In step #6, the output of the photometry circuit (325) is determined to be equal for the three distance measurement areas. In order to show that they are equivalent, a variable S=1 is set.In step #7, it is determined whether this is the first distance measurement using the variable ST.In this case, 5T=O and the first distance measurement is There is, so proceed to step #5.Step #
5, the auxiliary light emission signal ""lF+", l, 21
", "g, °゛ are all set to the "'High" level, and all auxiliary illumination lights can be projected. Step #9
In each signal “91°+, u, 2n”2. ” and projects the auxiliary illumination light.Next, in step #10, a counter T for monitoring the integration time of the CCD is output.
Reset and start. And step #1
1, a CCD drive start signal is transmitted via signal line "e". In step #12, it is determined whether the counter T is larger or smaller than a preset maximum integration time of the CCD. Here, it is assumed that T<(i-length integration time), and the process proceeds to step #22. In step #22, the signal "g+" is
is at the “Higl+” level.

Since the signal °'g1'' is set to the "Higb" level in step #5, the process advances to step #23.

In step #23, it is determined whether the integration completion signal "h1" of the CCD (300a) is at the "High" level. Here, it is assumed that the integration of the CCD (300a) has not yet been completed and the "111°" level is "Low". Then proceed to step #24, step #24.
In #25, steps #22. The same judgment as in #23 is made, and here it is assumed that the signal "g2" is at the "High" level and the signal "11□' is at the "Low" level, and the process proceeds to step #26. Step #26゜#
At step #27, step #22. for signals "g3" and "11." I made the same judgment as #23, and here,
Assuming that the signal "g3" is at the "High" level and the signals II, , and 11 are at the "Low" level, the process returns to step #12. As a result, steps #12→#22→#23→#24→#25-
A loop of #26→#27→#12 is formed, and in order to escape from this loop, T≧(
(longest integration time) or step #23 niorite signal u11. +1 is “High” level (CCD (300a
), or in step #25, the signal II 12°
00b) is completed), or at step #27, the signal ++1. , ++ is 'High' level (C
Either one of the following conditions must be met: CD (300c) has been integrated (end of integration). Here, in the middle of the loop several times, the signal “T” changes to “H” at step #25.
igl+" level is satisfied. In this case, proceed to step #31 and check whether the variable S indicating whether the output of the photometry circuit (325) is equivalent for the three distance measurement areas is 1. Determine.Step #6
In step #32, since S=1 is set.
Then, in step #32, the auxiliary light emission signal "RI" is set to the "Lou+" level.

Set “9z” to High level and “C” to Low level. Here, signal “112” first goes to
The fact that it has reached the gl+' level means that C0D (30
011) was completed first. Therefore, the amount of reflected light from the subject within the distance measurement area of the CCD (300t+) is the largest, and there is a high possibility that the closest subject will be included in the distance measurement area.
Only the distance measurement area of the CD (300b) is enabled as described later, and for the auxiliary light, only the signal “9□” is set to “9□” so that only the distance measurement area of the CCD (300b) is illuminated.
') ligb'' level.

Next, the process advances to step #36, and the signals “I, TI” are “H”.
iHb" level. Here, in step #32, the signals "i,, ++ are set to "Low" level, so proceed to step #39, step #3
9, the distance measurement calculation value regarding the data of the CCD (300a) is invalidated. Next, the process proceeds to step #40, where it is determined whether the signal "g2" is at the "High" level. Here, in step #32, signal II g2m
Since the CCD in the digital memory (302) is set to the "l-1-1i" level, the process advances to step #41.
Data is read from the address where the data (300b) is stored. Step # based on the read data
At step 42, a distance measurement calculation is performed to obtain a distance measurement calculation value for the CCD (300b).

Next, the process proceeds to step #44, where the signal “2.°” becomes “High”.
h” level. Here, in step #32, the signal “2.h” level is determined. ” is set to the “Low” level, so proceed to step #47 and select C0D (
Then, in step #48, a predetermined calculated value is selected from the distance calculated values for each CCD.

The selection method is not related to the present invention, so a description thereof will be omitted. Then, in step #49, a variable 5T=1 is set to indicate that the first distance measurement has been completed.

In the following, when the distance measurement is performed from the second time onward, 5T=1 has already been set in step #49, and in this state, the process returns to step #2 to check if the illumination area signal "a" is at the "High" level. judge whether As before,
Assuming that the illumination area signal "a" is at the "Higl+" level, the process proceeds to step #3, and in step #3, it is determined whether the outputs of the photometry circuit (325) are equivalent for the three distance measurement areas. . Here, as with the first distance measurement, if it is determined that they are equivalent, step #6
Proceed to and set S=1. Next, in step #7, it is determined whether it is the first distance measurement (S T = O), but since this is not the first distance measurement, step #7 is performed.
Proceed to 9. In step #9, the auxiliary light emission signal is output, but in step #32, "J," has already been set to '.
Since "Low" level and "IF2" are set to "Higl+" level II, , and ++ are set to "Low" level, the counter T is reset in the next step #1o in which this signal is output. , and transmits a COD drive start signal via the signal line II eI+ in step #11.Step #12
It is determined whether T≧(! & long bond time), and if this condition is not yet satisfied this time, the process proceeds to step #22. At step #22, the signal “9”
Since I'' is at the “Low” level, proceed to step #24.
Since the signal "g2' is at the "High" level, step #2
5, it is determined whether the signal "h2" is at the "Higb" level. If this condition is not yet met this time, the process proceeds to step #26. In step #26, the signal "fl" is at "Low" level, so the process returns to step #12. Therefore, step #12
A loop of →#22→#24→#25→#26→#12 is formed. As in the first distance measurement, if the signal "h2n" becomes "Higb" level in step #25 and the loop is exited, the process proceeds to step #31. Steps after step #31 are the same as in the first distance measurement. Since they are the same, duplicate explanations will be omitted.

Next, a case will be described in which the counter T becomes longer than the longest fractional time in step #12. However, the output of the photometry circuit (325) is the same for the three focus detection areas, and the illumination area signal "a" is "High".
Suppose that the level is First, in step #1, 5T=O is set to indicate that this is the first distance measurement. Next, in step #2, it is determined whether the illumination area signal "a" indicating whether an interchangeable lens (11) having a predetermined focal length is attached is at a "High" level. Here, the illumination area signal IIa" is "I-
l-1i" level, so proceed to step #3. In step #3, it is determined whether the outputs of the photometry circuit (325) are equivalent for the three distance measurement areas. Here, since they are equal, proceed to step #6. Step In step #6, S=1 is set to indicate that the output of the photometry circuit (325) is equivalent for the three distance measurement areas.In step #7, it is determined whether or not this is the first distance measurement using the variable ST.
Judge by. In this case, since it is the first distance measurement with 5T=0, the process proceeds to step #5. In step #5, the auxiliary light emission signal "c"l"lF2" is generated.

All "C" lights are set to the "Higl+" level, and all the auxiliary illumination lights are enabled to be projected. In step #9, the auxiliary light emission signals "2,""g2" and "3." are output, and the auxiliary illumination light is projected.Next, in step #10, the CCD integration time is monitored. Counter T
Reset and start. And step #11
At step #12, the CCD drive start signal is transmitted via the signal line "'e゛°. At step #12, the magnitude of the maximum integration time of the counter T and the preset CCD is determined. Here, it is assumed that T<(i length). Then, in step #22, it is determined whether the signal "g + " is at the "Higb" level. In step #5,
Since the signal “21°°” is set to the “Higb” level, the process proceeds to step #23. In step #23, the integration completion signal “h,” of the CCD (300a) is set to “°”.
It is determined whether the signal “b
, ” is at the “Low” level. Then, the process proceeds to step #24. In steps #24 and #25, the signal “g2
Step #22 for “and °°11□”. The same judgment as #23 is made, and here the signal “g2” is “Hi”.
It is assumed that the signal “1h2°” is at the “Low” level. And step #2
Proceed to step #26. At #27, the signal "2. ”
and “h,” step #22. The same judgment as #23 is made, and here the signal “c” is at the “High” level, and the signal “11.jll” is “”.
Then, the process returns to step #12. As a result, steps #12→#22→#23
→ #24 → #25 → #26-#27 → #12 loop is formed, and to escape from this loop, step #12
If T≧(maximum integration time) at step #2
3, the signal "h1" reaches the °'High" level (cc
D (300a) integration completed) or step #25
The signal “h2” is at the 'Higb' level (CCD
(300b) is completed), or in step #27, the signal “11.” becomes “I (igb” level) (CCD
(300a) (end of integration) must be satisfied.Here, it is assumed that the condition T≧(longest integration time) is satisfied in step #12 during some loop. In this case step #12
Step #1 transmits the COD drive end signal via the signal line "e+1". Then, in step #13, it is determined whether the illumination area signal "a" is at the "High" level. In this case, the illumination area signal "a" is at the "High" level. a" is at the "High" level, the process proceeds to step #14, and it is determined whether S=1. Since S=1 is set in step #6, the process proceeds to step #15. The gain amount of each CCD is read from the address where the analog gain amount of each COD is stored from the digital memory (302).Here, the gain amount of CCD (300a) is GA, and the gain amount of CCD (300b) is GB.
, C0D (300c) gain amount is GC. 0th order step #16. #18. In #20, each CC
The minimum values of the gains ff1GA, QB, and GC of D are determined. Here, a small gain amount means that the amount of light received by the CCD is large. If GB is the minimum value, proceed to step #19, where the auxiliary light emission signal '21°' is set to the 'Low' level, II g2H is set to the 'Higb' level, and 'gz' is set to the 'Low' level. This means that the amount of light reflected from the subject within the distance measurement area of the CCD (300b) is the highest, and there is a high possibility that the closest subject water will be included in the distance measurement area.
Only the distance measurement area of CD (300b) is valid as described below, and the auxiliary light is also effective for CCD (3001+).
Only the signals “Iig, n” are set to “High” level so as to illuminate the distance measurement area.

Next, the process advances to step #36, and the signal “g + ” becomes “Hi”.
gh” level.Here, step #
1 sets the signal "I?1" to "Low" level, so proceed to step #39. In step #39, the distance measurement calculation value related to the data of the CCD (300a) is invalidated. Proceed to step #40 and signal “2”
It is determined whether □°゛ is at the 'High' level.Since the signal '92' is set at the 'Higb' level in step #1, the process proceeds to step #41 and the data stored in the digital memory (302) is determined. Data is read from the address where the data of C0D (300b) is stored.Based on the read data, distance calculation is performed in step #42, and the distance calculation value for ccD (300b) is calculated. In step #44, the signal “Paha” becomes “Hi”.
gh” level.Here, in step #19, signal II and 11 are set to “Lo
w” level, so proceed to step #47 and C0
The distance measurement calculation value for D (300c) is invalidated. Then, in step #48, a predetermined calculated value is selected from the distance measurement calculated values for each CCD. And step #4
To indicate that the first ranging is completed at 9, S
Set T=1.

In the following, when the distance measurement is performed from the second time onward, 5T=1 has already been set in step #49, and in this state, the process returns to step #2, and in step #2, the illumination area signal IIa is set to "Higb". If the illumination area signal "a" is at the "High" level, the process proceeds to step #3, and in step #3 it is determined whether the output of the photometry circuit (325) is equal for the three distance measurement areas. As with the first distance measurement,
If it is determined that they are equivalent, proceed to step #6, and S
=1.

Next, in step #7, it is determined whether it is the first distance measurement (ST=O), but since this is not the first distance measurement, the process proceeds to step #9.In step #9, the auxiliary light emission signal is "sl", "2□", "9," are output, but "Fh" has already been set to 'L' in step #19.
og” level, “g2” to “High°° level,” “l”
Since "F3" is set to "Low" level, this signal will be outputted.In step #10, counter T is reset and started, and in step #11, it is output via signal line "e". and transmits a COD drive start signal.In step #12, T≧<y
If it is assumed that this condition is not yet satisfied this time, the process proceeds to step #22. In step #22, the signal "IIl" is "
Since the signal 'f12' is at the 'Low' level, the process proceeds to step #24. In step #24, since the signal 'f12' is at the 'High' level, the process proceeds to step #25, where '+12' becomes 'Hi.
gh” level.

Assuming that this condition is not yet met this time,
Proceed to step #26. In step #26, the signal 'high' is at "Low" level, so step #12
Return to Therefore, steps #12 → #22 → #24
→ #25 → #26 → #12 loop is formed. As in the first distance measurement, if the condition T≧(longest precision time) is satisfied in step #12, then step #1
The operations from step #121 onward to Step 21 are the same as those during the first distance measurement, so a redundant explanation will be omitted.

(Effects of the Invention) As described above, in the present invention, at the time of initial focus detection, all the light emitting parts in the auxiliary illumination device are emitted to illuminate all the focus detection areas, and the amounts of reflected light are compared and, for example, The focus detection area with the largest amount of reflected light is selected, and during subsequent focus detection, only the light emitting unit that illuminates the selected focus detection area emits light, so that the closest subject that will become the main subject is present. It is possible to select and illuminate the focus detection area that is likely to be the focus detection area, which has the effect of saving power consumption compared to the case where all the light emitting parts of the auxiliary lighting device always emit light.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram for explaining the principle of an active AP system used in an embodiment of the present invention, Fig. 2 is a perspective view showing the external appearance of a camera as an embodiment of the present invention, and Fig. 3 (
a) is a perspective view of the focus detection optical system used in the same as above, and FIG.
b) is a front view of the imaging optical member used in the above, FIG. 4 is an explanatory diagram showing an example of the photographing screen in the above, FIG. 5 is an explanatory diagram showing the relationship between the auxiliary illumination light flux and the focus detection area in the above, 6th
The figure is a cross-sectional view of the auxiliary lighting device used in the above, FIG. 7 is a block circuit diagram showing the configuration of the control system used in the above, and FIG.
9 is a block diagram showing the configuration of a photometric circuit used in the above, and FIG. 10 is a configuration diagram showing the arrangement of the photometric circuit in the camera. (2) are focus detection modules, (200a), (20
0b), (200c) are focus detection areas, (m),
(1), (r) are the illumination areas, (L D ,), (
LD,), (LD3) are light emitting parts, #5, #
9 is a step for lighting all the light emitting parts, #16. #18
．． #20. #23. #25. #27 is a step for comparing the amount of reflected light, #17. #19゜#21. #30. #3
2. #34 is a step for selecting an illumination area.

Claims (2)

[Claims] (1) Equipped with a focus detection device that has multiple focus detection areas within the shooting screen and multiple light emitting units that each emit illumination light flux that can illuminate each focus detection area, and when the focus detection device first detects focus, all The auxiliary lighting device includes an auxiliary lighting device that emits light from all the light emitting parts so that the focus detection area is illuminated, and a selection device that selects the focus detection area, and the auxiliary lighting device has a focus detection area selected by the selection device. An auxiliary illumination control system for a focus detection device, characterized in that the system is configured to sometimes emit light from only a light emitting section that illuminates the selected focus detection area. (2) The selection means is configured to compare the magnitude of the amount of reflected light from the subject of the illumination light flux for each focus detection area at the time of initial focus detection, and select the focus detection area with the largest amount of reflected light from the subject. An auxiliary illumination control system for a focus detection device according to claim 1, characterized in that: